function changepic(divob) {
    var obj=divob.firstChild;
    var link=obj.src;
    var y=link.lastIndexOf('.');
    var x=link.lastIndexOf('/');
    var str=link.substring(x+1,y);
    obj.src=link.replace(str,str+'_down');
}

function returnpic(divob) {
    var obj=divob.firstChild;
    var link=obj.src;
    var y=link.lastIndexOf('.');
    var x=link.lastIndexOf('/');
    var str=link.substring(x+1,y);
    var strrep=str.replace("_down","");
    obj.src=link.replace(str,strrep);
}

function mouseover(obj) {
    var link=obj.src;
    var y=link.lastIndexOf('.');
    var x=link.lastIndexOf('/');
    var str=link.substring(x+1,y);
    obj.src=link.replace(str,str+'_down');
}

function mouseout(obj) {
    var link=obj.src;
    var y=link.lastIndexOf('.');
    var x=link.lastIndexOf('/');
    var str=link.substring(x+1,y);
    var strrep=str.replace("_down","");
    obj.src=link.replace(str,strrep);
}